Temperature responsive switch



y 1950 L. BODDY 2,507,365

TEMPERATURE RESPONSIVE SWITCH Original Filed Feb. 13, 1942 \e \w O 13 7as 23 2+ 5 e0 65 es I [67 45 53 l 79 66 as H 7a 10 FYL u e\ L s\ 83 2.644 65 27 47 c2 3 2+ 72 46 4445 +3 23 m i I 71 1 U i e-m 73 a a? JINVENTOR. j LEONARD BoDnY Patented May 9, 1950 TEMPERATURE RESPONSIVESWITCH Leonard Boddy, Ann Arbor, Mich., assignor to The AndersonCompany, a corporation of Indiana Original application February 13,1942, Serial No. 430,785. Divided and this application January 5, 1946,Serial No. 639,263

12 Claims.

My invention relates generally to electrical switches and particularlyis directed to a switch responsive to temperature changes.

It has been found in internal combustion engines having a plurality ofcylinder blocks that, even though a common cooling system or radiator isprovided, one of the blocks may exceed a safe temperature, For example,in an internal combustion engine of the V-type it has been common toconnect the water jackets of the two cylinder blocks to a commonradiator and to provide forced circulation of the cooling fluid. In oneof the motor blocks there has been placed a temperature responsivedevice for transmitting current to an indicating instrument located onthe dashboard or instrument panel of the motor or vehicle. This providesan indication of the general operating temperature of the motor, but itis not sufiiciently sensitive to respond to an abnormal conditionoccurring in the other motor block. In accordance with the disclosure Iprovide means in one of the motor blocks to obtain an indication of thetemperature during normal operation and means in the other cylinderblock which will be responsive to any abnormal condition to provide anindication on the same instrument. In a broader view, the system isapplicable to any multi-unit device and includes means responsive to oneof the units to give a relative indication of the operating temperatureof all of the units, and to give an accurate indication of the operatingtemperature of that particular unit, and which further includes meansresponsive to each of the other units and effective whenever thetemperature of the associated unit exceeds a predetermined amount toproduce an indication on the instrument that at least one of the unitshas exceeded a safe or predetermined temperature.

The system above referred to is described in my copending applicationSerial No. 430,785, filed February 13, 1942, now abandoned. The presentapplication is a division of that copending application.

The primary object of the present invention is to provide a switchembodying improved principles of design and construction whereby theswitch may be employed in conjunction with various systems, includingthe one referred to.

A particular object of the invention is to provide a temperatureresponsive unit in which improved means are provided for positioning andresiliently supporting the operating mechanism of the unit.

An important object is to provide a switch structure embodying aSwitchback carrying terminal means and operating means provided withcontact means adapted for cooperation with the terminal means in apredetermined manner.

An additional object of the invention is to provide a switch comprisedof few parts which can be easily and quickly assembled together on aproduction basis.

Another object of the invention is to provide a switch which is verysensitive, yet positive and eflicient in operation.

Other and further objects of the invention will become more readilyapparent by reference to the following description taken in connectionwith the accompanying drawing, wherein:

Figure 1 is a fragmentary, largely schematic representation of thedevices and the circuit comprising the electrical indicating system ofsaid copending application;

Figure 2 is a cross-sectional view of the switch or temperatureresponsive unit, constituting the subject invention, illustrated in theupper left portion of Figure 1;

Figure 3 is a transverse section taken substantially on line 3-3 ofFigure 2;

Figure 4 is a top view of the operating mechanism of the unit depictedin Figure 2;

Figure 5 is a perspective view of the frame part which supports theoperating mechanism; and

Figure 6 is a perspective view of the resilient means employed forpositioning and resiliently mounting the operating mechanism in thehousing or casing of the switch.

In order to obtain a clear understanding of the application of thetemperature responsive unit or switch constituting the presentinvention, substantial portions of the disclosure in the said copendingapplication are submitted in the present application.

Accordingly, Figure 1 of the drawing shows a source of power or voltagesuch as battery It, one side of which is connected to the ground H. Thesource of voltage I0 may comprise a storage battery in a vehicle and, asis well known, this voltage source is subject to variations in voltage.The other side of the source of electrical power In is connected througha switch 12 to an indicating instrument l3 which is of the cumulativeresponsive type. This instrument is provided with a dial l4 havingindications thereon for cooperation with an indicating hand IS. Theindicating hand 15 is actuated through a member It by a bimetallicelement l1 suitably mounted at l8 upon the frame or case of theinstrument l3. An electrical heating element i9 is provided ported, acontact 24 supported adjacent the end of and by the bimetallic element23, a cooperating contact 25 mounted upon a suitable adjustable supportand conductor 26 which is positioned by an adjustable screw 21 mountedin'a fixed frame or support 28. The adjustable screw 21 mounted in thefixed support 23 is provided for adjustment of the position of the lowercontact 25 so as to accurately predetermine the temperature at which thebimetallic element 23 will open the contacts 24 and 25. The contact 25is positioned so as to cause interruption of the electrical circuitwhenever the temperature of the cooling medium within the block 22exceeds a predetermined amount. The lower contact 25 and the supportingconductor 26 are electrically connected to a heating element 3|surrounding a bimetallic element 32 supported within a temperatureresponsive device 33 which is supported within a suitable opening in thewater Jacket in the other motor block 34. The temperature responsivedevice 33 has the heating coil 3| for the bimetallic element 32connected to an electrical contact 35 mounted on the end of thebimetallic element 32. The electrical contact 35 is arranged tocooperate with an electrical contact 36 adjustably supported by a screw31 from a fixed support member 38. The adjustable contact 36 isconnected to ground 39 through the adjustable screw 31 and the support38. It therefore becomes apparent that there is provided a seriescircuit which may be traced from the ground through battery it, switchi2, heating coil l9 of the instrument i3, bimetallic element 23,contacts 24, 25, and the conductor 26 of the heat responsive device 2|and through the heating coil 3|,the contacts 35 and 36 to the ground 39in the heat responsive device 33.

The indicating instrument i3 is of the type which has the indicatinghand i5 positioned ad- Jacent the highest temperature on the scalewhenever a minimum amount of current or no current at all is beingreceived by the heating coil iii of the indicating instrument. Theelements within the heat responsive device 33 in the block unit 34 of amotor Or other device operates to transmit a series of impulses throughthe elements of the heat responsive device 2| to the indicatinginstrument l3. The action of the bimetallic element 32 of thetransmitting device 33 is such that the contacts 35 and 36 arealternately opened and closed at a relatively high rate so as totransmit impulses varying in frequency and in duration. Irrespective ofthe condition of the source of power it the transmitting device 33requires that for each temperature or each condition of the variablefactor to be indicated there must be supplieda certain amount of heattothe bimetallic element 32. As the amount of heat received by thetransmitting device 33. from the surrounding medium or from the motorblock 35 increases, less electrical power is required to produceperiodical opening and ciosing of the contacts 35 and 36- so that adecreased amount or power is received by the heating coil l9 locatedabout or adjacent to the bimetallic element II of the indicatinginstrument l3. When this occurs the indicating hand I5 is moved toward ahigher indication. If the electrical circuit is interrupted by theopening of the switch i2, no power is received by the heating coil |9 ofthe indicating instrument so that the bimetallic element cools to movefrom the warped position shown in the drawing to a substantiallystraight position thereby moving the hand 15 to the highest indicationon the dial l4. If, while the switch |2 is closed, the heat responsivedevice 2| reaches a temperature beyond a predetermined amount which hasbeen considered the limit to which the motor block 22 may be safelyheated, the bimetallic element 23 will open the contacts 24 and 25thereby causing an indication to be produced on the instrument i3showing that inone of the units of the motor the safe predeterminedtemperature has been exceeded.

From the circuit arrangement shown and described it will be noticed thatthe bimetallic element 23 of the heat responsive unit 2| serves as aconductor for the impulses being transmitted through the circuit. Thisproduces an operation which is deemed to be desirable. If it is assumedthat an abnormal condition is developing in the motor block unit 22, thetemperature thereof is rapidly increasing. Due to the heating efiect ofthe current passing through the bimetallic element 23 of the heatresponsive device 2 I, the contacts 24 and 25 will be opened at atemperature which is slightly below, by a few degrees, the temperaturewhich should not be exceeded for any length of time in order to preventdamage to the operation of the motor. Since the temperature of that unitof the motor is increasing, more and more heat is being transmitted tothe temperature responsive device 2| so that the bimetallic element, 23will continue to remain in a position where the contacts 24 and 25 willremain open thereby preventing an operating condition for a periodwherein these contacts might open and close several times while thetemperature of the motor unit is passing through the upper limit of thepredetermined safe temperature. Thus, the switch contacts 24 and 25 willnot have a period of operation which might be in step with the openingand closing of the contacts 35 and 36 of the unit 33 thereby delayingthe indication of the abnormal condition on the instrument i3 since thisinstrument is responsive to the cumulative effect of current transmittedthrough the circuit. While for purposes of illustration Figure 1 showsbut one unit 2| responsive to a temperature in excess of a predeterminedamount, it of course will be apparent that in a multi-unit device havingmore than two units, a plurality of series connected devicescorresponding to device 2i will be employed. Eachunit except one willhave a device corresponding to device 2| and the remaining unit will beprovided with a temperature responsive device corresponding to thedevice 33 which provides a continuous accurate indication of theoperating temperature of that unit and also provides a relativeindication of the operation of all units so long as there is no abnormal.operation of any one of the individual units.

Thus the aggregate power transmitted by a series of impulses by thetemperature responsive device 33 will vary inversely with respect toincreases in the temperature or variable factor to be indicated. Sincethe indicating instrument i3 is one which in respect to the aggregatepower received in the form of current impulses to produce an indicationof decreased value upon an increase in the aggregate power received itis apparent that when a minimum amount of power or no power is receivedby the instrument that the indication is a maximum value. This maximumvalue is equal to or in the vicinity of the temperature value abovewhich it is unsafe to continue the operation of the motor.

In Figure 2 there is shown a cross-sectional view of a temperatureresponsive device such as 2| shown in Figure 1. This device comprises atubular casing 4| suitably soldered or secured to a, support member 42which is provided at one end with threads for cooperation with thethreads in the opening of the motor block, and at the other end withsuitable surfaces which may be gripped by a wrench of tool to insurethat the temperature responsive device is properly mounted in the motorblock so as to prevent leakage of the cooling medium. The inside of thesupporting member 42 is suitably recessed at 43 so as to receive aswitchback or block of insulating material 44 which is disposed againstsuitable packing 45 and retained in position by a washer 46, ring 47,and peening over the support member. The insulating member 44 completelycloses the passage to the interior of the casing or housing 44, andprovides means for conducting current to and from the interior byrelatively rigid terminal contact means 48 and 49. These terminals 48and 49 are preferably flat and extend through the insulating material 44in spaced apart parallel relation.

The operating mechanism of the switch as illustrated in Figures 4through 6 constitutes an assembly or unit that is adapted fordisposition in the casing or housing prior to fastening the Switchbackin place. This assembly, among other things, includes the frame 28. Thisframe is preferably elongated and channel-shaped, comprising a generallyplanar top wall 50 and side walls 54. The top wall is provided with ahole 52 at one extremity for the reception of a rivet 53 and a threadedaperture 54 at its other e tremity for the screw 27. The top wall isalso provided with openings 55 and 55.

The inner extremity of resilient contact means 51 is secured in lappedengagement with the outer end of the bimetallic strip 23 by the rivet53. This rivet also serves to secure the conductor 25 and a flexibleelongated flat tongue 58 of insulation to the frame 28. The strip 23 andthe conductor 25 are insulated from each other except at 24 and 25 andwith respect to the frame 28 by suitable insulation. More specifically,in this respect, an insulator sleeve 59 surrounds the rivet 53 andpasses through an insulating washer 60 disposed on one side of theframe, through the tongue 58 engaging the opposite side of the frame,and through an insulating washer 6! disposed between the head 52 of therivet and the conductor 26. The outer resilient extremity of theconductor 26 and the outer extremity of the resilient contact means 57are preferably substantially identical in character. Each includes a.lateral curved or bowed portion 63 and an onturned end portion 64. 63are adapted to be received between and resiliently engage the terminalportions 48 and 49, when the Switchback 44 is secured in place. The endportions 64 of the contact means are insulated from each other by theinsulator tongue 58 which is preferably of a width greater than thewidth of the resilient portions of the contact The curved portions meansand extends an appropriate distance in advance of the ends.

The contact 24 adjacent the inner free extremity of the bimetallic stripor element 23 normally engages the contact 25 carried by the inner endof the conductor 26, as alluded to above. The contact 25 and theconductor 26 are insulated from the screw 21 by an insulating washer 65.The screw enables the contact 25 to be adjusted so as to determineaccurately the temperature at which the element 23 will open or breakthe circuit between the contacts 24 and 25. It will be noted in Figure 5that the top wall 50 of the frame is split through the aperture 54. Thisarrangement causes the material definin the aperture to resiliently gripthe screw and automatically lock the same to any position to which itmay be adjusted. The end 66 of the element 23 is guidingly received in agenerally rectangular opening 67 provided in the upper extremity 68 ofan insulating part 69. The part 69 is seated in a transverse positionagainst an indentation 10 formed in the end wall of the housing 44, andconsequently is spaced inwardly from the remainder or" the end wall toprovide sufficient clearance for the operating end of the element 23.Thus, when a predetermined temperature has been exceeded to cause theelement 23 to open the contacts 24 and 25 the element will be limited inits movement by the engagement of its end 65 with the upper marginaledges of the opening 87 to prevent the element from contacting the housing 4 l.

The housing M is preferably provided with a pair of correspondinglongitudinally extending grooves constructed and arranged whereby toform generally curved and square channel portions 1! and 72,respectively, which are joined together by shoulder portions it. asillustrated in Figure 3. The upper extremity 68 and the lower extremityof the inslulator part 59 are disposed in the square and curvedchannels, respectively, of the housing.

As stated above, one particular object of the invention is toresiliently support the operating mechanism in the housing. This in partis accomplished by associating a resilient mounting M with the frame 28as clearly illustrated in Figures 2, 3, 4 and 6. The mounting ispreferably generally channel in shape and, among other things, includesa base wall 75 and side walls 716 which engage the top wall 50 and sidewalls 5! of the frame, respectively. The base wall '55 preferablyincludes a pair of longitudinally extending portions 71 connectedtogether by bridge portions 18 and 19, the portions being formed bysuitable cutouts or openings and M which register with an opening 82 andthe opening 56 in the frame, respectively. The frame 28 is provided withan indented cross-portion B3 and a pair of oppositely disposed spacedlugs 84. The bridge portion 18 of the mounting is also correspondinglyindented and the same is true of the bridge portion 79 which projectsinto the space between the lugs 84, all of which serves to provideclearance for the operation of the element 23.

The mounting I4 is preferably ailixed to the frame 28 by providing themounting with two pairs of locking projections 85 and 86 which extendinto the cutouts 55 and 5B and are bent over against the under surfaceof the top wall 50 of the frame. The side walls 16 of the mounting arepreferably provided with curved resilient end continuations 81 which areadapted to resiliently bear against the inner surface of the curvedaccuses be evident that it is a simple matter to secure the switchback.in place so that the terminal contact means 48 and 19 carried therebyreceive and are resiliently engaged by the resilient contact means; .andthat the operating means is sealed within the confines of the housing.Moreover, it will be manifest that the insulating part 59 provides astop for the inner extremity for the frame 28 for limiting movement ofthe mechanism in one direction and that the free end of the tongue 58may engage the carrier or block 45 for limiting the movement of themechanism in another direction. The resilient mounting provides meanswhereby the switch mechanism may be gradually eased into the housingwithout in any way affecting the set positions of the sensitive parts.

While for the purpose of simplicity in illustration and to facilitatethe description of the operation of my invention, there has been shownthe application of my invention to a water-cooled motor having twocylinder blocks, it of course will be apparent that my invention may beapplied to any other devices having the same or a greater number ofunits in which it is desired to obtain an indication of the operatingtemperature of one of the units and an indication whenever apredetermined temperature is exceeded in any of the otherunits; Forexample, the invention is ;applicable to a multi-cylinder air-cooledengine in which case a device corresponding to the teminterrupt thecircuit to produce an indication on.

the instrument telling the observer that an abnormal condition exists.

It therefore will become apparent that I am not to'be'limited by thespecific disclosure or description since it is apparent thatmodifications may be made in the instruments, in the number ofinstrumentalities employed, and in the circuit arrangement withoutdeparting from the spirit and. scope of my invention as set forth in theappended claims. I

I claim: 1'. Operating mechanism for an electric switch including, aframe, an elongated contact, disposed substantially, on one side of theframe, a

s'ulator may be moved direct a portion of said elongated contact in apredetermined plane.

2. Operatirm mechanism for an electric switch comprising, a frameprovided with an opening, an elongated resilient contact connected atone end to one extremity of the frame, a flexible elongated contactsecured adjacent one end to the said one extremity of said frame, theother end of said flexible contact projecting into said opening forengagement with the other end of said resilient contact, and means formoving one con .tact with respect to the frame.

3. Operating mechanism for an electric switch comprising, a frameprovided with an opening, an elongated resilient contact connected atone end to one extremity of the frame, a flexible elon= gatedcontactsecured adjacent one end to the said one extremity of said frame,the other end of said flexible contact projecting into said open ing forengagement with the other end of said resilient contact, and means forsimultaneously moving the other ends of said contacts in a predetermined plane.

4. An operating mechanism for an electric switch including a frame, amovable contact her/=- ing a portion disposed at one side of the frame,another contact and a bimetallic element disposed at the other side ofsaid frame, means securing and insulating said movable contact, saidanother contact, and said element with respect to said frame, and meanswhereby the movable contact may be adjusted relative to said anothercontact.

resilient contact and a bimetallic element disposed adjacent theopposite side of said frame, fastening means passing through said frame,through an intermediate portion of said elongated contact, saidresilient contact and through said element in V a manner whereby saidframe is insulated there- 5. An operating mechanism for an electricswitch including a frame, a movable contact hav= ing a portion disposedat one side of the frame, another contact and a bimetallic elementdisposed at the other side of said frame, means securing and insulatingsaid movable contact, said another contact, and said element with re=spect to said frame, means whereby the movable contact may be adjustedrelative to said another contact, and means carried by said frame arranged to provide a yieldable support for said operating mechanism.

6. An operating mechanism for an electric switch including a metalframe, an elongated contact member having a portion disposed at one sideof the frame, another contact member and. a bimetallic member disposedat the other side of said frame, fastening means passing through all ofsaid members, means insulating the frame from such members, meansinsulated from the contact members for effecting relative adjust menttherebetween, and means carried by said frame arranged to provide ayieldable support for said operating mechanism.

8. An operating mechanism for an electric switch comprising a frame, anelongated contact having yieldable extremities, means for connect-= ingan intermediate portion of this contact with respect to one side of theframe, contact means mounted on and insulated with respect to anotherside of the frame and having yieldable par from. an insulator, and meanswhereby said int8 films disposed opp s e he yieldable extremities ofsaid elongated contact, an insulator arranged to prevent electricalengagement between one of the yieldable extremities of the elongatedcontact and an adjacent yieldable portion of the contact means andbetween the elongated contact and said frame, and means providedadjacent the other yieldable extremity of the elongated contact and theother adjacent yieldable portion of the contact means for efiectingrelative adjustment therebetween. v

9. An operating mechanism for an electric switch comprising a frame, anelongated contact having yieldable extremities, means for connecting anintermediate portion of this contact with respect to one side of theframe, contact means mounted on and insulated with respect to anotherside of the frame and having yieldable portions disposed opposite theyieldable extremities of said elongated contact, an insulator arrangedto prevent electrical engagement between one of the yieldableextremities of the elongated contact and an adjacent yieldable portionof the con tact means and between the elongated contact and the frame,and means carried by said frame arranged to provide a yieldable supportfor said operating mechanism.

10. An operating mechanism for an electric switch comprising a metalframe, a flat insulator member engaging one side of the frame, anelongated contact membe engaging said insulating member and havingyieldable extremities, an insulating washer engaging the outer surfaceof said elongated contact member, a pair of insulator members disposedat the opposite sides of the frame, a pair of overlapping contactmembers arranged between said pair of insulator members and havingportions located adjacent the yieldable extremities of said elongatedcontact member, fastening means extending through the frame, contactmembers, and insulator members for holding the same assembled, meansinsulating the fastening means from the frame and contact members, andone of said insulator members being provided with a part arrangedbetween a yieldable extremity of the elongated contact member and anadjacent portion of one of the pair of contact members whereby toprevent electrical contact therebetween.

11. An operating mechanism for an electric switch including a frame, amovable contact having a portion disposed at one side of the frame,another contact and a bimetallic element disposed at the other side ofsaid frame, means securing and insulating said movable contact, saidanother contact, and said element with respect to said frame, and meanswhereby one contact may be adjusted relative to the other.

12. An operating mechanism for an electric switch including a frame,means on said frame providing a resilient support for said operatingmechanism, a movable contact having a portion disposed at one side ofthe frame, another contact and a bimetallic element disposed at theother side of said frame, means securing and insulating said movablecontact, said another contact, and said element with respect to saidframe, and means whereby one contact may be adjusted relative to theother contact.

LEONARD BODDY.

REFERENCES CITED The following references are of record in the

